For now, highway officials have stopped construction of a Texas 151 underpass after an endangered spider was discovered in the area.

For now, highway officials have stopped construction of a Texas 151 underpass after an endangered spider was discovered in the area.

Photo: Mike Fisher

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Biologist Jean Krejca, PHD. , inspects a small cave uncovered by earthmoving equipment whereTxDOT was building an underpass along Texas 151 near Loop 1604. Endangered spiders were found in the small feature, halting construction work as Biologist study the rare spiders. Friday, Sept. 7, 2012. less

Biologist Jean Krejca, PHD. , inspects a small cave uncovered by earthmoving equipment whereTxDOT was building an underpass along Texas 151 near Loop 1604. Endangered spiders were found in the small feature, ... more

Photo: Bob Owen, San Antonio Express-News

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One of our readers has what he thinks if the solution to the rare and endangered species of spiders that were disocvered in this cave recently, when TxDot workers were grading land along Texas 151 near Loop 1605

One of our readers has what he thinks if the solution to the rare and endangered species of spiders that were disocvered in this cave recently, when TxDot workers were grading land along Texas 151 near Loop

TxDOT workers Joshua Donat, left, Stirling Robertson, right, and Biologist Jean Krejca, center, inspect a small cave they found as construction workers were grading land along Texas 151 near Loop 1604 for an underpass. Endangered spiders were found in the small feature, halting construction work as Biologist study the rare spiders Friday, Sept. 7, 2012.

TxDOT workers Joshua Donat, left, Stirling Robertson, right, and Biologist Jean Krejca, center, inspect a small cave they found as construction workers were grading land along Texas 151 near Loop 1604 for an

Biologist Jean Krejca, PHD. , inspects a small cave uncovered by earthmoving equipment whereTxDOT was building an underpass along Texas 151 near Loop 1604. Endangered spiders were found in the small feature, halting construction work as Biologist study the rare spiders. Friday, Sept. 7, 2012.

Biologist Jean Krejca, PHD. , inspects a small cave uncovered by earthmoving equipment whereTxDOT was building an underpass along Texas 151 near Loop 1604. Endangered spiders were found in the small feature,

Eric Otero, Project Manager with TxDOT, removes thermal material protecting the climate in a small cave where endangered spiders were found after construction workers encountered the small cave while grading land along Texas 151 near Loop 1604 for an underpass. Endangered spiders were found in the small feature, halting construction work as Biologist study the rare spiders Friday, Sept. 7, 2012.

Eric Otero, Project Manager with TxDOT, removes thermal material protecting the climate in a small cave where endangered spiders were found after construction workers encountered the small cave while grading

“Bottom line is we are waiting to hear from them,” said Gary Mowad, the Fish and Wildlife Texas administrator. “I'm sure they will formulate a new plan that will get them moving forward again. They always do.”

But that might not immediately reassure area residents and drivers, who likely will wait for some time before TxDOT releases a new design and even longer before anything is built.

“There's no timeline at all right now,” Donat said.

The agency has identified the area as one of the city's most congested, with about 80,000 vehicles a day at Texas 151 and Loop 1604.

Generally, underpasses are cheaper to build than overpasses. Building an overpass now could also result in higher construction costs in the future, Donat said. If the state ever decided to build highway flyovers, that could mean adding a third level of traffic.

TxDOT will now pay Ballenger for the work it's done so far, along with the cost of packing up the construction site, which is standard for all TxDOT contracts.

TxDOT learned that the rare spider, called a Braken Bat Cave meshweaver, was living underground at the construction site Aug. 29. It was only the second known sighting; the first was 30 years ago.

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One of nine endangered karst invertebrates in Bexar County, it was added to the federal protection list in 2000.

Because the cave where the spider was recently found is its only known occupied habitat — the habitat where it was first seen no longer exists, sealed up and covered by a housing development — TxDOT must protect it according to federal law.

George Veni, executive director of the National Cave & Karst Research Institute, who first discovered the Braken Bat Cave meshweaver, encouraged TxDOT to start doing intensive biological research in nearby caves to see whether there are more endangered spiders living there.

If such a site is found and protected, Veni said, it would give TxDOT more room to negotiate with the Fish and Wildlife Service about how much should be done to protect the cave in the path of the 151 project.

“Right now, the Fish and Wildlife Service is between a rock and hard place,” Veni said. “One site is essentially destroyed, and the other is the site of the underpass. ... Doing the biological work, from what I'm reading, is dirt cheap in comparison to rerouting or anything else.”

Donat pointed out one bright spot: None of the construction had affected the Texas 151 main lanes yet; all the work had been limited to the highway median, where crews discovered the spider.

“The find came at the right time to have something like this happen, so we aren't in the way, we aren't holding people up,” Donat said. “Traffic's still the same as it's been the last six months, 10 months. But it's not any worse. That's a huge victory.”

In the meantime, until a new design is approved, TxDOT will work not to disturb possible habitats and will return the construction site to its natural state, as if no endangered spider the size of a dime was ever discovered there and brought a multimillion-dollar project to its knees.